A leaded glass window can break and may need to be repaired. This process requires patience and the proper tools. When there is broken glass in a leaded panel, window or other glass piece, you will need to use your experience of cutting glass and the following process to repair leaded glass.
According to Joe Ring, owner of J. Ring Glass Studio, you can shine up old glass that has become dull due to being dirty, weathered, or poorly cleaned over the years. Wash the old glass, with a clean towel, in a 7 percent lye and 93 percent water solution. Rinse in a 20 percent vinegar and 80 percent water solution, and then rinse in just water. This will make it easier to match with replacement glass.
Select a new sheet of glass that matches the stained glass piece that needs to be replaced.
Decide which way the grain will go and determine which part of the new sheet of glass will best match the glass that needs to be replaced.
Remove Damaged Glass
Place the stained glass piece on a work surface, back side up.
Cut the top of the lead, with a lead cutter, around the broken glass.
Firmly grip one end of the lead, using pliers or needle nose pliers, and pull to rip it away from the glass. Remove just enough lead so you can dislodge the broken glass.
Remove the glass, keeping it as close to its shape as possible. The front side and channel will remain intact.
Clean the channels of the lead to remove all small shards of glass and the grout.
Cut Replacement Piece
Place the old pieces of glass on the new sheet of glass, as closely to the shape as possible. Trace the shape with a non-permanent marker
Slide a piece of paper under the open spot in the stained glass piece, if the old piece is shattered, and trace the shape of the empty lead. Cut the shape out and trace the shape onto the new sheet of stained glass.
Cut the new piece of stained glass, with the stained glass cutter and grozier pliers, slightly larger than either of the traced patterns.
Place the new glass into an open area of the stained glass piece. Mark the glass where additional grinding is necessary.
Grind a little at a time and insert the new piece of glass into the channel of the lead.
Measure a new piece of lead to the size needed to cover the glass. With a lead cutter, cut the top of the lead away from the channel. Place over the new piece of glass.
Place flux on the joints and solder the ends of the new lead, where it intersects with the existing lead.
Press putty under the new lead and clean. Let sit for 24 hours to dry.